Virtual private networks (VPNs) may be used by enterprises and network communication companies to securely separate the traffic exchanged with different customers from each other. VPNs also simplify the administration of customer networks by allowing geographically diverse locations to appear to all be on a single private network. This allows the customer network administrators to link these geographically diverse locations via a third party network without regard to the third party networks other customers, or the underlying structure of the third party network.
A technology that may be used to help implement a VPN is virtual routing and forwarding (VRF). VRF allows multiple instances of a routing table to exist on a network element such as a router or switch. Because these multiple instances are independent, overlapping internet protocol addresses can be used without interfering with each other. Each of these instances may be referred to as a virtual router because they appear to other network elements to be a physical router even though they are a software construct.